[单选题]
The reason the position of a particle cannot (m f 7 uw d+ir.8bh7zec8l(eeibe specified with infinitqb -c:lf7:wtj2x-hxie precision is thecf:-wq j-t:7xihx2 bl
A. exclusion principle.
B. uncertainty principle.
C. photoelectric effect.
D. principle of relativity.
